TTree::Print("toponly") inserts extra newline between listed items.
Cause is the use of custom defined variant of Printf() in TString.h. In this variant of std printf, newline character is automatically added at the end of the formatted text.
This has not been reflected in definition of TTree::Print(), see TTree.cxx Line 7035 (https://root.cern.ch/doc/master/TTree_8cxx_source.html#l07035), where additional newline character was left in the string to be printed.
Suggested fix: remove '\n' from the format string on line 7035 in TTree.cxx